qemu/rules.mak
Paolo Bonzini 3bc2f570ec build: replace weak symbols with a static library
Weak symbols were a nice idea, but they turned out not to be a good one.
Toolchain support is just too sparse, in particular llvm-gcc is totally
broken.

This patch uses a surprisingly low-tech approach: a static library.
Symbols in a static library are always overridden by symbols in an
object file.  Furthermore, if you place each function in a separate
source file, object files for unused functions will not be taken in.
This means that each function can use all the dependencies that it needs
(especially QAPI stuff such as error_setg).

Thus, all stubs are placed in separate object files and put together in
a static library.  The library then is linked to all programs.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Tested-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Tested-by: Stefan Weil <sw@weilnetz.de>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
2012-11-18 19:19:23 +00:00

118 lines
3.6 KiB
Makefile

# Don't use implicit rules or variables
# we have explicit rules for everything
MAKEFLAGS += -rR
# Files with this suffixes are final, don't try to generate them
# using implicit rules
%.d:
%.h:
%.c:
%.m:
%.mak:
# Flags for dependency generation
QEMU_DGFLAGS += -MMD -MP -MT $@ -MF $(*D)/$(*F).d
%.o: %.c
$(call quiet-command,$(CC) $(QEMU_INCLUDES) $(QEMU_CFLAGS) $(QEMU_DGFLAGS) $(CFLAGS) -c -o $@ $<," CC $(TARGET_DIR)$@")
ifeq ($(LIBTOOL),)
%.lo: %.c
@echo "missing libtool. please install and rerun configure"; exit 1
else
%.lo: %.c
$(call quiet-command,$(LIBTOOL) --mode=compile --quiet --tag=CC $(CC) $(QEMU_INCLUDES) $(QEMU_CFLAGS) $(QEMU_DGFLAGS) $(CFLAGS) -c -o $@ $<," lt CC $@")
endif
%.o: %.S
$(call quiet-command,$(CC) $(QEMU_INCLUDES) $(QEMU_CFLAGS) $(QEMU_DGFLAGS) $(CFLAGS) -c -o $@ $<," AS $(TARGET_DIR)$@")
%.o: %.m
$(call quiet-command,$(OBJCC) $(QEMU_INCLUDES) $(QEMU_CFLAGS) $(QEMU_DGFLAGS) $(CFLAGS) -c -o $@ $<," OBJC $(TARGET_DIR)$@")
LINK = $(call quiet-command,$(CC) $(QEMU_CFLAGS) $(CFLAGS) $(LDFLAGS) -o $@ $(sort $(filter %.o, $1)) $(filter-out %.o, $1) $(LIBS)," LINK $(TARGET_DIR)$@")
%$(EXESUF): %.o
$(call LINK,$^)
%.a:
$(call quiet-command,rm -f $@ && $(AR) rcs $@ $^," AR $(TARGET_DIR)$@")
quiet-command = $(if $(V),$1,$(if $(2),@echo $2 && $1, @$1))
# cc-option
# Usage: CFLAGS+=$(call cc-option, -falign-functions=0, -malign-functions=0)
cc-option = $(if $(shell $(CC) $1 $2 -S -o /dev/null -xc /dev/null \
>/dev/null 2>&1 && echo OK), $2, $3)
VPATH_SUFFIXES = %.c %.h %.S %.m %.mak %.texi %.sh
set-vpath = $(if $1,$(foreach PATTERN,$(VPATH_SUFFIXES),$(eval vpath $(PATTERN) $1)))
# find-in-path
# Usage: $(call find-in-path, prog)
# Looks in the PATH if the argument contains no slash, else only considers one
# specific directory. Returns an # empty string if the program doesn't exist
# there.
find-in-path = $(if $(find-string /, $1), \
$(wildcard $1), \
$(wildcard $(patsubst %, %/$1, $(subst :, ,$(PATH)))))
# Generate files with tracetool
TRACETOOL=$(PYTHON) $(SRC_PATH)/scripts/tracetool.py
# Generate timestamp files for .h include files
%.h: %.h-timestamp
@test -f $@ || cp $< $@
%.h-timestamp: %.mak
$(call quiet-command, sh $(SRC_PATH)/scripts/create_config < $< > $@, " GEN $*.h")
@cmp $@ $*.h >/dev/null 2>&1 || cp $@ $*.h
# will delete the target of a rule if commands exit with a nonzero exit status
.DELETE_ON_ERROR:
# magic to descend into other directories
obj := .
old-nested-dirs :=
define push-var
$(eval save-$2-$1 = $(value $1))
$(eval $1 :=)
endef
define pop-var
$(eval subdir-$2-$1 := $(if $(filter $2,$(save-$2-$1)),$(addprefix $2,$($1))))
$(eval $1 = $(value save-$2-$1) $$(subdir-$2-$1))
$(eval save-$2-$1 :=)
endef
define unnest-dir
$(foreach var,$(nested-vars),$(call push-var,$(var),$1/))
$(eval obj := $(obj)/$1)
$(eval include $(SRC_PATH)/$1/Makefile.objs)
$(eval obj := $(patsubst %/$1,%,$(obj)))
$(foreach var,$(nested-vars),$(call pop-var,$(var),$1/))
endef
define unnest-vars-1
$(eval nested-dirs := $(filter-out \
$(old-nested-dirs), \
$(sort $(foreach var,$(nested-vars), $(filter %/, $($(var)))))))
$(if $(nested-dirs),
$(foreach dir,$(nested-dirs),$(call unnest-dir,$(patsubst %/,%,$(dir))))
$(eval old-nested-dirs := $(old-nested-dirs) $(nested-dirs))
$(call unnest-vars-1))
endef
define unnest-vars
$(call unnest-vars-1)
$(foreach var,$(nested-vars),$(eval $(var) := $(filter-out %/, $($(var)))))
$(shell mkdir -p $(sort $(foreach var,$(nested-vars),$(dir $($(var))))))
$(foreach var,$(nested-vars), $(eval \
-include $(addsuffix *.d, $(sort $(dir $($(var)))))))
endef